Nearly 10 million people saw the premiere of “House of the Dragon” on Sunday, Aug. 21, making the “Game of Thrones” spinoff HBO’s most-watched series premiere in the network’s history.

HBO aired the episode four times on premiere night and it was also streamed on HBO Max. The viewership number is only going to increase in the coming weeks.

For instance, the “Game of Throne” series finale in May 2019 was seen on its first night by 19.8 million, more than any other series episode on HBO, the Nielsen company said. HBO estimates that some 46 million people in total have seen it, when delayed viewing is taken into account.

Anticipation for “House of the Dragon” was evident in how many people were streaming old “Game of Thrones” episodes on HBO Max, which the network fed by offering crisper picture quality. The weekly average of streams in August is nearly 90 percent above June, the network said.

“House of the Dragon” takes place two centuries before the events of the original series, which ended its hit eight-season run in 2019. The story focuses on House Targaryen, made famous in “Game of Thrones” by Emilia Clarke’s Daenerys and her fearsome dragons. But don’t expect “House of the Dragon” to be a remake of “Game of Thrones,’’ cast member Steve Toussaint said.

“It’s been done and they did it exceedingly well,” said Mr. Toussaint, who plays the very rich Lord Corlys Velaryon. “You know you’re in that world, but you’re seeing a different story, different characters, different motivations.”

Among the new faces in the clan is Prince Daemon Targaryen, played by Matt Smith. His villainous character is a lot more complex than he appears to be on first viewing, the actor said.

“I think the reason I’ve had fun is because he’s maybe not just a villain,” he said. “I think there’s actually a huge amount of fragility and depth and inner madness there. ... It’s not black and white. It can go either way with Daemon at any point.”

Based on George R.R. Martin’s “Fire and Blood,” the drama was co-created by Martin and Ryan Condal, whose credits include the 2016-19 sci-fi drama “Colony.” Mr. Condal is an executive producer and co-showrunner with director Miguel Sapochnik, who brings his experience on “Game of Thrones” to the prequel.

“House of the Dragon,” much like its predecessor, focuses on familial succession with a female heir being overlooked. But Mr. Sapochnik notes a key difference between the two series: The team making the prequel is more diverse, including a 50-50 split between male and female directors, including Mr. Sapochnik, Clare Kilner, Geeta Vasant Patel and Greg Yaitanes.

There was a conscious push to be inclusive behind the scenes, Mr. Sapochnik says.

“We really tried to, as much as possible, hire as many female crew as we could, because we think that’s a really important shift that needs to be both recognized, acknowledged, acted upon, maybe give opportunities to people who don’t get op- portunities,” he explained.

The team making “Dragon” is equally as diverse, and — for the fantasy genre — boasts a relative bounty of women in the writers’ room. The gender balance affects the show’s story and tone, according to some of its female cast members.

The ensemble cast also includes Emily Carey, Graham McTav- ish, Fabien Frankel, Rhys Ifans and Sonoya Mizuno.